This invention relates to an electronic appliance to which one of a plurality of appliances is selectively connected and which is subject to remote control. An embodiment of the invention is preferably used, for example, for a television set to which one of a plurality of video appliances is selectively connected at the video input terminals thereof and which is subject to remote control.
Normally, a VTR (video tape recorder) is connected in most cases to an external video input terminal of a conventional television set for domestic use. In the case of a television set which is remotely controlled using a commander, where a VTR is connected to a video input terminal of the television set, a remote control signal for controlling the VTR is received at a remote control signal receiver of the television set and then transmitted to the VTR.
However, in recent years, novel appliances have been developed and accordingly kinds of appliances which can be connected to a video input terminal of a television set have increased so that, in addition to a VTR, for example, a video camera, an 8 mm video recorder, a video disk player and so on may be connected. Accordingly, television sets having a plurality of video input terminals have also been provided.
FIG. 2 illustrates a system wherein appliances such as a VTR 5, an 8 mm video recorder 6 and a video disk player 7 are connected to a television set 4 which has three video input terminals 1, 2, 3, and those appliances 4, 5, 6, 7 are remotely controlled using a commander 8.
Referring to FIG. 2, the appliances 5, 6, 7 are connected to the video input terminals 1, 2, 3 via connecting lines or cables 9, 10, 11, respectively. The television set 4 includes a remote control signal receiver 12 for receiving an infared ray remote control signal from the commander 0, and a remote control signal received at the signal receiver 12 is then transferred to a control circuit 13 provided in the television set 4 while the remote control signal is transferred also to control circuits 14, 15, 16 provided in the appliances 5, 6, 7, respectively, over a connecting line or cable 17.
The television set 4 further includes an input control circuit 18 and an input switching circuit 19 therein. Signals which are delivered from the appliances 5, 6, 7 via the terminals 1, 2, 3, respectively, are coupled to the input switching circuit 19. Which one of the appliances 5, 6, 7 is selected, that is, which one of the terminals 1, 2, 3 is selected, is determined in response to an external operation of a keyboard or the like associated with the input control 18. Thus, in response to such an external operation, the input control circuit 18 controls the input switching circuit 19 to effect a switching operation to transfer a signal received at one of the terminals 1, 2, 3 of the television set 4 to an image receiving circuit (not shown).
The commander 8 includes various operating keys 20 and a terminal selection switch 21. The selection switch 21 may be in the form of a slide switch having four discrete positions including a position for selection of the television set 4 in which the television set 4 receives a television broadcast in response to a selection by the input switching circuit 19 and three other positions for selection of the three terminals 1, 2, 3. Some of the operating keys 20 are in common for the appliances 4, 5, 6, 7, and when a commonly used operating key 20 is operated, a remote control signal having a code corresponding to a selection, that is, a selected position, of the selection switch 21 is transmitted therefrom. Such commonly used keys include, for example, a channel selection button of a VTR of a television set and a still or pause button of a VTR or a video disk player.
According to the construction described above, in case, for example, the VTR 5 is to be selected via the input control circuit 18 by an external operation, the selection switch 21 of the commander 8 will be shifted to the position for selection of the terminal 1. Then, if an operating key 20 is operated, a remote control signal is transmitted therefrom and is received at the receiver 12. The remote control signal is then transferred to the control circuit 13 while it is delivered also to the control circuit 14 for the VTR 5 over the connecting line 17. Consequently, the VTR 5 is caused to operate in a mode corresponding to the contents of the code of the remote control signal. Thus, in the case of, for example, a reproduction or play mode, a reproduction or play signal is received via the terminal 1 over the connecting line 9 while it is further supplied to the image receiving circuit described above via the input switching circuit 19. Consequently, a reproduced picture image of the VTR 5 can be monitored on the screen of the television set 4.
Also the other 8 mm video recorder 6 or the video disk player 7 can be caused to operate in a desired mode by remote control by a shifting operation of the selection switch 21 to a position corresponding to the terminal 2 or 3.
In the conventional system of FIG. 2, it is necessary to operate the selection switch 21 of the commander 8 each time the input of the terminal 1, 2 or 3 is to be switched. Accordingly, time or labor for such operation is required, and in case an operation of the selection switch 21 is forgotten or effected in error, it is impossible to control the appliances regularly. To the contrary, if the selection switch 21 is omitted, it will be impossible to use some of the operating keys 20 commonly to the appliances 4, 5, 6, 7, and consequently the number of such operating keys 20 will have to be increased for individual kinds of appliances to be connected to the television set 4.